use `group_by()` instead

[emagar]

In ubuntu 22.04 with a fresh R 4.3.2 installation, I got this warning after invoking slide():

Lagging cycle by 1 time units.

Warning message: group_by_() was deprecated in dplyr 0.7.0. ℹ Please use group_by() instead. ℹ See vignette('programming') for more help ℹ The deprecated feature was likely used in the DataCombine package. Please report the issue at https://github.com/christophergandrud/DataCombine/issues. This warning is displayed once every 8 hours. Call lifecycle::last_lifecycle_warnings() to see where this warning was generated.

lifecycle::last_lifecycle_warnings() [[1]] <warning/lifecycle_warning_deprecated> Warning: group_by_() was deprecated in dplyr 0.7.0. ℹ Please use group_by() instead. ℹ See vignette('programming') for more help ℹ The deprecated feature was likely used in the DataCombine package. Please report the issue at https://github.com/christophergandrud/DataCombine/issues.

---

Backtrace: ▆

1. └─DataCombine::slide(...)
2. └─dplyr::group_by_(data, .dots = GroupVar)

3. └─dplyr:::lazy_deprec("group_by")